OK, so the drive was relatively short (only about 10-15 minutes) so couldn't really gauge battery life in any significant way. Out of respect for the owner, no pictures of the car will be posted, however it looks identical to this one:
The car is the 90D, not the faster P90D, so it is 415HP with 485lb-ft of torque. It does zero to 60 in 4.4 seconds and that is REALLY easy to do I discovered.
Patman: The huge screen/GPS shows you the location of all the charging stations (which are free). This car was not subscribed to the Auto Pilot feature.
HTSS_TR: Handling is surprisingly good, you can really feel the low centre of gravity. The AWD makes it feel significantly different from the M5, it is not tail-happy at all, if you power into a turn you can't seem to get the rear-end to step out. It comes shod in some factory Michelin tires which are surprisingly good (they are not PSS's or anything like that). It has multiple ride height options, though we spent the majority of the time with it in "Sport" which drops the car down a bit (not sure on the exact amount).
Performance:
Acceleration is like taking off in a really fast jet. With the AWD and torque of the electric motors, it just hooks solid and pulls like a freight train. The eerie silence and lack of shifting just adds to the experience. The car feels very balanced, but heavy. The weight being so low I'm sure aides in how well it sticks.
Controls:
The controls on the absolutely massive LCD take some getting used to but the screen is fantastic. There are no real buttons other than the one on the end of the gear selector. Interior space is extremely generous since there is no transmission tunnel or traditional centre console. The floor is completely flat save for the "tray" that is on the floor between the seats.
Comfort/fit and finish:
This one is going to be a bit subjective but here we go: The M5 was better put together inside. Better materials choice, better seats, better door handles, it felt far more like you were in a cockpit piloting the car than in the Tesla, which felt more like a Ford Fusion. The seats were decent, but not as good as the ones in the M5 or SRT-8 Charger. The M5 had the best factory seats I've experienced. The door trim and handles had a plastic feel to them, which surprised me at the price point ($110K). The M5 had soft-touch, leather and brushed aluminum. The Charger has decent door panels (suede) and I might posit them being a bit better here too (the bolster on the Charger panels attaches to the door in a funny fashion which doesn't affect functionality but has a strange appearance, that's my biggest gripe with them). The M5 and SRT-8 both have better steering wheels as well. Better materials, better feel.
Door panel spacing (between the door and pillar) and trim spacing was a little off, which surprised me. The M5 was perfectly uniform here. Exterior was much better with everything lining up like it should.
Ride:
The ride quality was very good, likely due in part to the weight as well. It was not harsh on sport, but retained composure over bumps. NVH was excellent, there was very little road noise and of course zero engine or drivetrain noise. On long drives it strikes me as being very relaxing to drive. Due to how heavy it feels, I can't really compare the ride to the M5 or the Charger, it is different, I can't say better or worse.
Overall I can really see the draw of the car for somebody who loves tech, like myself. However, at this price point, I expected a better interior. The gadgets and features are all really nice, but they don't excuse the fit and finish. The acceleration is addictive, so I doubt I would get anywhere near EPA driving it regularly. It is very easy to see why these cars are selling, but I would say this is primarily due to the tech and gadgets, not the luxury, which I believe BMW, Mercedes and Audi all do better at this price point.
